The invention relates to a circuit for internal illumination of motor vehicles in which controller automatically turns the internal illumination on and off as a function of the operating state parameters of the motor vehicle, according to a predetermined switching program.
A circuit of this type known from German Patent Document 28 54 729. This circuit is used in the vehicles built by Bayerische Motoren Werke AG. According to the used embodiment of the circuit, there is a manually operable switch in the vicinity of one of the internal illuminating fixtures which has three switch positions. In one position the switch switches the control device for performing the switching program. In another position, the internal illumination is switched on permanently. In the third position the internal illumination is switched off. A problem produced by the switching program, in which, after leaving the vehicle or after entering the vehicle, the internal illumination remains switched on for a certain period of time after the vehicle doors are finally closed, is that the vehicle user does not know, after the vehicle doors are closed, whether the switching program is turned on and the internal illumination will be switched off automatically or whether the internal illumination is set to remain on. The controller likewise does not give the unknowing vehicle user any indication.
There is also an additional problem that arises from the circuitry of the switch. The switch described has one terminal as the positive pole of the electrical system. This requires costly wiring, a high weight of the current-carrying wire, and special insulating measures.
An object of the present invention is to provide a switching arrangement of the initially-described type in which a change of the operating mode of the internal illumination can be accomplished at low circuit-design expense.
This and other objects are achieved by the present invention which provides a circuit for internal illumination of motor vehicles comprising a controller, coupled to the internal illumination, that automatically turns the internal illumination on and off as a function of operating state parameters of the motor vehicle according to a predetermined switching program, wherein the controller is a deliberately operable electrical controller. The circuit also includes a control device, coupled to and controlled by the controller, that switches the switching program off and the internal illumination permanently on in response to being controlled by the controller.
The present invention provides a low-load control line to the control device. There is no longer any doubt about the effective operating mode of the internal illumination, since the switching program is basically set and internal illumination remains switched on only following a deliberate actuation of the controller. In other words, if the vehicle user, before leaving the vehicle, does not deliberately actuate the controller, he can be sure that the internal illumination will be switched off according to the switching program after he leaves the vehicle. On the other hand, if he has actuated the controller, depending on the design, the internal illumination can remain switched on after leaving the vehicle or at least until the person has left the vehicle. In the latter case, the light is then switched off according to the switching program after leaving the motor vehicle.
The present invention offers considerable advantages as far as weight, electrical safety, and operating comfort of the vehicle user are concerned.
The design of the invention can have different forms. Thus the switching time of the internal illumination in the "permanently on" mode can be limited with respect to time. It has been found that an interval of 15 minutes for example after finally leaving the motor vehicle or after switching on this operating mode is desirable.
The time limit can also be set to a shorter value when, because of the behavior of the vehicle user, it is evident that he no longer requires the internal illumination. It may be advantageous in this regard to switch off the internal illumination when giving a locking command for a vehicle door or for the central locking system of the motor vehicle, immediately or after a delay of several seconds.
In certain embodiments, this switching off occurs when the electrical system of the motor vehicle is in a switching state characteristic of shutting down. For example, this will occur when the ignition of the motor vehicle is turned off. Again, switching off can be delayed, for example, after the final closing of the vehicle doors.
In addition to setting the "permanently on" mode for the internal illumination, in certain embodiments it is possible to actuate the controller again to deliver a switching command to the controller which switches the controller back to the switching program operating mode. This measure is used when the vehicle user, for example with the vehicle parked, considers the constant switching on of the internal illumination to be no longer necessary, but also does not intend to leave the vehicle.
It can also be advantageous if the internal illumination can be switched off permanently, although the vehicle doors are open for example. Such a case occurs when the motor vehicle is in a repair shop. In addition, with the aid of the same controller, a different switching command can be delivered to the controller. Instead of an additional controller provided for the purpose, this offers a considerable advantage as far as the number of required components is concerned.
In this differently designed switching command, for example, multiple brief actuation of the controller onto its switching position or an adjustment of the controller in its switching position for a specific space of time, may be involved. The latter can be accomplished by the controller remaining in its control position for a period of several seconds, i.e. a period of time which is completely unusual for conventional command and operating processes, and then returned from this state back to its basic position.
The controller itself can be a switch of any design. In contrast to the design of the switch as a toggle switch, the design of the switch as a pushbutton switch has the advantage of simple design and ease of operation .